Useful electrophilic trifluoromethylating agents; S-, Se- and Te-(trifluoromethyl)dibenzo-thio-, -seleno- and -telluro-phenium-3-sulfonates

Article abstract of DOI:10.1016/0022-1139(95)03253-A

S, Se- and Te-(Trifluoromethyl)dibenzo-thio-, -seleno- and -telluro-phenium-3-sulfonates and their dimethyl and nitro derivatives have been synthesized in good yield by sulfonation of the corresponding (trifluoromethyl)dibenzocyclic chalcogen salts with fuming sulfuric acid or by sulfonation followed by nitration.The practical use of these power-variable trifluoromethylating agents has been demonstrated.Thus, they provide good yields of trifluoromethylated products, and the by-product (a salt of dibenzothiophene-3-sulfonic acid or an analog) was easily removed from the products by filtration or by washing with water.S-(Perfluoro-ethyl, -n-butyl- and -n-octyl)dibenzothiophenium-3 sulfonates have also been synthesized and a similar perfluoroalkylation using one of them has been accomplished. - Keywords: Electrophilic trifluoromethylating agents; Perfluoroalkylation; S-(Trifluoromethyl)dibenzothiophenium sulfonates; Se-(Trifluoromethyl)-dibenzoselenophenium sulfonates; Te-(Trifluoromethyl)dibenzotellurophenium sulfonates; NMR/IR spectroscopy